# US 7,746,485 B2 · Determining physical property of substrate

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 7,746,485 B2
- Document ID: US7746485B2
- Status: Granted
- Kind: B2
- Application number: 12/253,160
- Filed: 2008-10-16
- Published: 2009-02-05
- Granted: 2010-06-29
- Earliest claimed: 2006-12-15
- Assignees: Applied Materials, Inc.
- Inventors: Abraham Ravid; Boguslaw A. Swedek; Jeffrey Drue David; Jun Qian; Ingemar Carlsson; Dominic J. Benvegnu; Harry Q. Lee; Lakshmanan Karuppiah
- Web page: https://patentgrep.com/patent/US7746485B2

## CPC

- G01B 11/0683: {measurement during deposition or removal of the layer}
- G01B 11/0625: {with measurement of absorption or reflection}
- G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS

## Abstract

A method of determining a physical property of a substrate includes recording a first spectrum obtained from a substrate, the first spectrum being obtained during a polishing process that alters a physical property of the substrate. The method includes identifying, in a database, at least one of several previously recorded spectra that is similar to the recorded first spectrum. Each of the spectra in the database has a physical property value associated therewith. The method includes generating a signal indicating that a first value of the physical property is associated with the first spectrum, the first value being determined using the physical property value associated with the identified previously recorded spectrum in the database. A system for determining a physical property of a substrate includes a polishing machine, an endpoint determining module, and a database.

## Claims

### Claim 1

A method of determining a physical property of a substrate, the method comprising:
polishing a surface of a substrate;
storing in a database a plurality of previously recorded spectra, each of the previously recorded spectra having a physical property value associated therewith stored in the database;
during polishing, directing a beam of white light to impinge the surface of the substrate and generate a reflected light beam and measuring a first spectrum of the reflected light beam;
determining a second spectrum from the plurality of previously recorded spectra stored in the database that matches the first spectrum, wherein the second spectrum matches the first spectrum when the second spectrum is similar to the first spectrum; and
identifying from the database the physical property value stored in the database associated with the second spectrum.

### Claim 2 (depends on 1)

The method of claim 1, wherein the physical property value is a value of a physical property selected from the group consisting of: a layer thickness on the substrate and a step height on the substrate.

### Claim 3 (depends on 2)

The method of claim 2, wherein the physical property is a layer thickness on the substrate.

### Claim 4 (depends on 2)

The method of claim 2, wherein the physical property is a step height on the substrate.

### Claim 5 (depends on 1)

The method of claim 1, wherein multiple second spectra from the database are determined to match the first spectrum and multiple physical property values associated with the multiple second spectra are identified.

### Claim 6 (depends on 5)

The method of claim 5, further comprising calculating a resulting value from the multiple physical property values associated with the multiple second spectra.

### Claim 7 (depends on 6)

The method of claim 6, wherein calculating includes extrapolation of the resulting value from the multiple physical property values.

### Claim 8 (depends on 1)

The method of claim 1, wherein a sequence of first spectra of the reflected light beam are measured as the substrate undergoes polishing.

### Claim 9 (depends on 8)

The method of claim 8, wherein a sequence of second spectra are determined to match the sequence of first spectra, and a sequence of physical property values associated with the sequence of second spectra are identified.

### Claim 10 (depends on 9)

The method of claim 9, further comprising determining a linear function for the physical property value from the sequence of physical property values.

### Claim 11 (depends on 1)

The method of claim 1, wherein determining a second spectrum includes determining only one spectrum that matches the first spectrum.

### Claim 12 (depends on 1)

The method of claim 1, wherein:
determining a second spectrum includes determining multiple spectra that are similar to the first spectrum; and
identifying from the database the physical property value includes calculating the average of the values associated with the multiple spectra that are similar to the first spectrum.

### Claim 13 (depends on 1)

The method of claim 1, wherein determining a second spectrum includes determining only one spectrum that matches the first spectrum.

### Claim 14

A computer program product tangibly embodied in a computer-readable storage device, the computer program product including instructions that, when executed, cause a processor to perform operations comprising:
causing a surface of a substrate to be polished;
storing in a database a plurality of previously recorded spectra, each of the previously recorded spectra having a physical property value associated therewith stored in the database;
receiving a measurement of a first spectrum of a reflected light beam from the surface of the substrate;
determining a second spectrum from the plurality of previously recorded spectra stored in the database that matches the first spectrum, wherein the second spectrum matches the first spectrum when the second spectrum is similar to the first spectrum; and
identifying from the database the physical property value stored in the database associated with the second spectrum.

### Claim 15 (depends on 14)

The computer program product of claim 14, wherein the physical property value is a value of a physical property selected from the group consisting of: a layer thickness on the substrate and a step height on the substrate.

### Claim 16 (depends on 15)

The computer program product of claim 15, wherein the physical property is a layer thickness on the substrate.

### Claim 17 (depends on 15)

The computer program product of claim 15, wherein the physical property is a step height on the substrate.

### Claim 18 (depends on 14)

The computer program product of claim 14, wherein multiple second spectra from the database are determined to match the first spectrum and multiple physical property values associated with the multiple second spectra are identified.

### Claim 19 (depends on 18)

The computer program product of claim 18, further comprising calculating a resulting value from the multiple physical property values associated with the multiple second spectra.

### Claim 20 (depends on 19)

The computer program product of claim 19, wherein calculating includes extrapolation of the resulting value from the multiple physical property values.

### Claim 21 (depends on 14)

The computer program product of claim 14, wherein a sequence of first spectra of the reflected light beam are measured as the substrate undergoes polishing.

### Claim 22 (depends on 21)

The computer program product of claim 21, wherein a sequence of second spectra are determined to match the sequence of first spectra, and a sequence of physical property values associated with the sequence of second spectra are identified.

### Claim 23 (depends on 22)

The computer program product of claim 22, further comprising determining a linear function for the physical property value from the sequence of physical property values.

### Claim 24 (depends on 14)

The computer program product of claim 14, wherein:
determining a second spectrum includes determining multiple spectra that are similar to the first spectrum; and
identifying from the database the physical property value includes calculating the average of the values associated with the multiple spectra that are similar to the first spectrum.

### Claim 25

A system for determining a physical property of a substrate, the system including:
a polishing machine for polishing a surface of a substrate;
a light source to generate a light beam of white light and direct the light beam onto a surface of the substrate during polishing and generate a reflected light beam;
a detector to measure a first spectrum of the reflected light beam; and
a computer programmed to
store in a database a plurality of previously recorded spectra, each of the previously recorded spectra having a physical property value associated therewith stored in the database,
determine a second spectrum from the plurality of previously recorded spectra stored in the database that matches the first spectrum, and
identify from the database the physical property value stored in the database associated with the second spectrum.